Используя conditional ii или iii if we (throw away) less rubbish our planet would be cleaner/ if ) you, i would join greenpeace if you had read these books you (know) more about enviromental problems. if people (avoid) damaging nature many species of animals wouldnt have disappeared !
If we threw away less rubbish our planet would be cleaner.
If I were you, I would join Greenpeace.
If you had read these books, you would have known more about environmental problems.
If people had avoid damaging nature, many species of animals wouldn't have disappeared.